The present invention relates to loader boom assemblies for self-propelled loaders which are controlled to maintain the forward ends of the boom assembly in a generally vertically linear path throughout a substantial portion of the upward travel of the boom assembly.
Loader boom assemblies which provide a generally vertical movement of a bucket used for lifting material have been used. For example U.S. Pat. No. 4,355,946 illustrates a lift arm control linkage structure for a loader which uses a long lift arm support link at the rear portions of the loader boom assembly, to provide an altered upward path of a front bucket, and at the same time provides bucket leveling.
U.S. Pat. No. 3,215,292 issued to Halls on Nov. 2, 1965 illustrates guide links which operate to cause lift arms of a loader to extend out at the same time they are raised. However, in this unit the bucket continually moves outward from the supporting machine as the bucket raises, rather than moving on a generally vertical path in the upper portions of the range of movement.